In mobile communication networks, there is always a challenge to obtain good performance and capacity for a given communications protocol, its parameters and the physical environment in which the mobile communication network is deployed.
The evolution of the Universal Mobile Telecommunications Standard Long Term Evolution (UMTS LTE) for mobile communications continues with new features to increase the overall capacity and to increase the general performance of the communications network. Coordinated Multi-point transmission/reception (CoMP) is one concept that was first introduced in Release 10 of LTE. In CoMP, UEs (user equipment, which in LTE is the terminology for the mobile communication terminals) can receive coordinated data transmissions from multiple sectors or cells.
In CoMP scenarios, it may be advantageous to map transmitter (TX) antenna ports of the network node to geographically separated antennas at different transmission points (TPs) within a cell of the base. Commonly there may be in the order of 1 to 8 antenna ports. The antenna ports are then geographically non-co-located, meaning that each antenna port may have different channel properties, like delay spread, Doppler spread, signal-to-noise ratio (SNR) and frequency offset.
A UE may thus face new challenges when receiving data transmissions from non-co-located antenna ports. In principle, the UE cannot assume antenna ports to be co-located and should hence estimate the channel properties separately for each antenna port.
Existing solutions to estimate the channel properties, e.g. the delay spread, are mainly based on the Cell Reference Symbols (CRS) and use a large number of samples (channel estimates) in time and frequency to give reliable estimates of the channel properties. Averaging over CRS ports may then be used to further improve the estimates.
However, there is still a need for an improved estimation of channel properties.